Let me start this by saying BUYER BEWARE. I bought my 5 series in september of 2010 (its a 2011) I read some great reviews and was very excited about getting this seemingly incredible edition to the legacy of BMW's great engineering. I purchased the addtle seat ventilation package for 2995.00 because I thought I was getting air conditioned seats.
What I was getting was this: Active seat ventilation.

"Keeping you feeling fresh even on the longest journey: the active seat ventilation ensures that air circulates throughout the seat constantly, removing moisture and helping prevent discomfort or driving fatigue."

"A total of nine axial flow fans are integrated into the high-quality foam padding inside the seat: four in the backrest and five in the seat. The fans draw fresh [b]cabin air[b] into the seats and channel it through an air-permeable middle layer, distributing it evenly throughout the seat. Special perforations in the upholstery allow it to move through the leather, keeping perspiration to a minimum.
The three-speed fans can be controlled using a switch on the central console or a control on the seat itself, depending on your BMW model. The iDrive Controller lets you change the distribution of air between the seat and the backrest. The highest fan speed instantly cools seats that have been heated by direct sunlight, ensuring a comfortable welcome even in summer.
In order to prevent uncomfortable over-cooling of the seat surface, the active seat ventilation includes seat heating, which heats the air to a perfectly comfortable temperature. Long journeys become more comfortable, the driver remains alert and fresh, and - last but not least - clothes are left less creased"
This was taken directly from BMW's website.

Here's the problem... I just brought my car in because I thought it was broken! My Car sits in an outdoor parking lot and because I live in L.A. it gets pretty toasty when the sun hits the seats. The seats conduct that heat and when you turn on the seat "FANS" they blow hot air! down your neck! I have a 1/2 hour drive home and although the ac cooled the inside cabin temp pretty quickly, 5 min's or so, the air the seat blows remained hot at first then warm for the duration of my drive cause the seat is warm. Blow cabin air through the hot seat and you get hot air. FAIL!
I know BMW is a long way from L.A. but I cannot believe they could not engineer this so that the air from the ac unit is actually blowing through the seats! The real dissapointment is I paid extra for this feature cause the heated seats came with the cold weather package! out the door my car was over $73'000.00 I cannot believe this is the best they could do!

Then again this is the same company that decided to make the run flat tires standard and disssed the spare tire I have already replaced 2 of those and the car ony has 14,000. miles on it. (485 bucks a piece installed)